Perioperative outcomes, complications, and costs associated with lumbar spinal fusion in older patients with spinal stenosis and spondylolisthesis.

OBJECT: The purpose of this study was to quantify the perioperative outcomes, complications, and costs associated with posterolateral spinal fusion (PSF) among Medicare enrollees with lumbar spinal stenosis (LSS) and/or spondylolisthesis by using a national Medicare claims database. METHODS: A 5% systematic sample of Medicare claims data (2005-2009) was used to identify outcomes in patients who had undergone PSF for a diagnosis of LSS and/or spondylolisthesis. Patients eligible for study inclusion also required a minimum of 2 years of follow-up and a claim history of at least 12 months prior to surgery. RESULTS: A final cohort of 1672 patients was eligible for analysis. Approximately half (50.7%) had LSS only, 10.2% had spondylolisthesis only, and 39.1% had both LSS and spondylolisthesis. The average age was 71.4 years, and the average length of stay was 4.6 days. At 3 months and 1 and 2 years postoperatively, the incidence of spine reoperation was 10.9%, 13.3%, and 16.9%, respectively, whereas readmissions for complications occurred in 11.1%, 17.5%, and 24.9% of cases, respectively. At 2 years postoperatively, 36.2% of patients had either undergone spine reoperation and/or received an epidural injection. The average Medicare payment was $36,230 ± $17,020, $46,840 ± $31,350, and $61,610 ± $46,580 at 3 months, 1 year, and 2 years after surgery, respectively. CONCLUSIONS: The data showed that 1 in 6 elderly patients treated with PSF for LSS or spondylolisthesis underwent reoperation on the spine within 2 years of surgery, and nearly 1 in 4 patients was readmitted for a surgery-related complication. These data highlight several potential areas in which improvements may be made in the effective delivery and cost of surgical care for patients with spinal stenosis and spondylolisthesis.

Crossing the Cervico-Thoracic Junction in Long Posterior Cervical Fusions Reduces Caudal Adjacent Segment Pathology.

STUDY DESIGN: Retrospective case control. OBJECTIVES: The purpose of this study is to compare clinical outcomes and rates of symptomatic caudal adjacent segment pathology (ASP) in posterior cervical fusions (PCF) constructs with end-instrumented vertebrae in the cervical spine (EIV-C) to PCF constructs that end in the proximal thoracic spine (EIV-T). METHODS: Retrospective review of 1714 consecutive cervical spinal fusion cases was done. Two groups were identified: 36 cervical end-instrumented vertebra patients (age56 ± 10 yrs) and 53 thoracic EIV patients (age 57 ± 9 yrs). Symptomatic ASP was defined as revision surgery or nerve root injection (or recommended surgery or injection) at the adjacent levels. RESULTS: EIV-C patients had a significantly higher rate of caudal-level symptomatic ASP requiring intervention compared with EIV-T patients (39% vs 15%, p = 0.01). The development of caudal-level ASP was highest at C7 (41%), followed by C6 (40%). The overall complication rate and surgical revision rates, however, were similar between the groups. Neck Disability Index outcomes at 2 years postop were significantly better in the EIV-T group (24.5 vs. 34.0, p = 0.05). CONCLUSIONS: Long PCF that cross the C-T junction have superior clinical outcomes and reduced rates of caudal breakdown, at the expense of longer fusions and higher EBL, with no increase in the rate of complications. Crossing the C-T junction affords protection of the caudal adjacent levels without adding significant operative time or morbidity.

Minimum 5-year radiographic results of long scoliosis fusion in juvenile spinal muscular atrophy patients: major curve progression after instrumented fusion.

BACKGROUND: Previous studies reported on spinal muscular atrophy (SMA) scoliosis surgery outcomes without focus on major curve progression (MCP). The purpose of this study was to assess minimum 5-year radiographic outcomes, MCP, and factors for MCP after spinal surgery in juvenile SMA patients with open triradiate cartilage at the time of surgery. METHODS: Retrospective review of radiographic and clinical data of 22 SMA patients treated surgically at 3 institutions over 20 years was performed. Major curve Cobb angle, apical vertebral translation, pelvic obliquity, coronal balance, and sagittal Cobb angles (T5-T12 and T12-sacrum) were measured at preoperative, initial, and ultimate follow-up. MCP was defined as an increase in Cobb angle of ≥ 10 degrees between initial and ultimate follow-up. RESULTS: Overall, SMA patients had significant improvement in radiographic measurements at follow-up. Eight patients (36%) developed MCP and were similar in age (7.8 vs. 8.8 y, P=0.09) to non-MCP patients. Initial major curve Cobb angle correction was greater for MCP patients than for non-MCP patients (19 vs. 36 degrees, P=0.004). MCP patients lost 26 degrees (P=0.001) and non-MCP patients lost 2 degrees of major curve Cobb angle correction during follow-up. Both groups had similar ultimate follow-up radiographic outcomes and remained improved from preoperative deformity. All 14 non-MCP patients had long posterior instrumentation (T4 or higher to sacrum/pelvis), whereas all 4 patients with short posterior instrumentation developed MCP. Six patients underwent anterior-posterior spinal fusion (ASF-PSF) and had greater preoperative deformity than PSF-only patients, but ultimate major curve Cobb angle (38 vs. 44 degrees, P=0.4) was similar for both the groups. Two ASF-PSF patients developed MCP. CONCLUSIONS: Overall, SMA patients maintained scoliosis correction with nonpedicle screw-based (predominantly Luque-Galveston instrumentation) long spinal instrumentation at minimum 5-year follow-up. MCP >10 degrees developed in 36%, contrary to our expectation of 100% in these young juvenile SMA patients. All non-MCP patients had instrumentation from the upper thoracic spine (T1 to T4) to the sacrum, whereas all 4 patients with short instrumentation developed MCP. MCP and non-MCP patients had similar ultimate correction and remained improved from preoperative deformity. Skeletal immaturity and length of posterior instrumentation may influence MCP in SMA scoliosis surgery and should be considered during preoperative planning. LEVEL OF EVIDENCE: Case Series; Level IV.

The role of concurrent fusion to prevent spinal deformity after intramedullary spinal cord tumor excision in children.

OBJECTIVES: Spinal deformity is a common development after laminectomy and resection of pediatric intramedullary spinal cord tumors. Our objective is to compare the occurrence of postlaminectomy spinal deformity in children with intramedullary spinal cord tumors that underwent decompression with fusion at the time of surgery to those that did not undergo fusion. METHODS: A retrospective chart review of 255 children with spinal cord tumors treated at 2 tertiary pediatric cancer centers between was performed. Of these, 52 patients with a biopsy-proven intramedullary spinal cord tumor had complete clinical records and radiographic data. Preoperative spinal alignment, surgical treatment, postoperative deformity, and risk factors for deformity were evaluated. All patients had at least 2-year follow-up. RESULTS: There were 18 females and 34 males with an average age of 8.1 ± 4.1 years. The average time to latest follow-up was 7.6 ± 5.3 years. Moderate or severe postresection spinal deformity (scoliosis > 25 degrees and/or sagittal plane abnormality > 20 degrees requiring bracing or surgery) developed in 57% (21/37) of resections without fusion (laminectomy or laminoplasty alone), and in 27% (4/15) of those with fusion (P = 0.05). Among skeletally mature children, 18 of 28 (64%) developed deformity after laminectomies and laminoplasties, compared with 22% (2/9) of the patients in the fusion group (P = 0.03). Removal of >3 lamina (P = 0.04) was associated with development of postoperative deformity. CONCLUSIONS: In the surgical treatment of patients with intramedullary spinal cord tumors, those that undergo instrumentation or in situ fusion at the time of spinal cord tumor excision are significantly less likely to develop postresection spinal deformity. LEVEL OF EVIDENCE: 3, Retrospective comparative study.

Anterior spinal fusion for thoracolumbar scoliosis: comprehensive assessment of radiographic, clinical, and pulmonary outcomes on 2-years follow-up.

BACKGROUND: There is a continued role for anterior spinal fusion (ASF) in the treatment of thoracolumbar scoliosis. Despite numerous previous reports of ASF in the treatment of thoracolumbar scoliosis, no single study has simultaneously evaluated clinical, radiographic, and pulmonary function outcomes. METHODS: Retrospective review of 31 consecutive thoracolumbar adolescent idiopathic scoliosis patients (Lenke type 5) who underwent ASF by a single surgeon. Patient records were comprehensively assessed for Scoliosis Research Society (SRS)-22 score, apical trunk rotation, radiographic changes, and pulmonary function before surgery and at 2-years follow-up. RESULTS: Thoracolumbar/lumbar curve correction averaged from 45 to 11 degrees (74%) and spontaneous correction of thoracic curves averaged from 26 to 15 degrees (42%). Instrumented segment lordosis increased by 11 degrees, whereas proximal junction kyphosis increased by 3 degrees. No significant changes were noted in T2-T12 kyphosis, distal junctional kyphosis, T12-S1 lumbar lordosis, or coronal balance. Thoracolumbar apical trunk rotation improved from 12 to 3 degrees. Average SRS scores significantly improved from 3.9 to 4.4. SRS assessments of self-image and pain also improved significantly from 3.6 to 4.5 and from 4.1 to 4.6, respectively. Absolute and percent predicted forced vital capacity and forced expiratory volume in 1 second were unchanged. Two patients suffered mild intercostal neuralgia postthoracotomy. There were no other complications. CONCLUSIONS: The thoracoabdominal anterior approach for thoracolumbar scoliosis facilitates excellent clinical and radiographic outcomes, minimal blood loss, powerful apical trunk rotation correction, relative maintenance of lordosis, relatively short fusion constructs, and improved SRS-22 performance, without significant pulmonary function impairment at 2 years. It continues to be an efficacious treatment for thoracolumbar scoliosis. LEVEL OF EVIDENCE: Level IV.

Pulmonary function changes after various anterior approaches in the treatment of adolescent idiopathic scoliosis.

STUDY DESIGN: Prospective radiographic and chart review of pulmonary function in patients who underwent 3 different anterior spinal surgery approaches for adolescent idiopathic scoliosis (AIS). OBJECTIVE: To assess the impact on pulmonary function in patients with AIS after anterior surgical approaches, including open thoracotomy, thoracoscopic with and without thoracoplasty, and thoracoabdominal 2 years after surgery. SUMMARY OF BACKGROUND DATA: Potential advantages of anterior surgery in the treatment of AIS include saving of distal motion segments and improving kyphosis restoration in the thoracic spine, possibly at the cost of pulmonary function impairment. Although thoracoscopic spinal instrumentation and fusion has recently been shown to induce less pulmonary impairment compared with open thoracotomy, no study has evaluated the effect of thoracoplasty as an adjunct to thoracoscopic surgery, nor the effects of the thoracoabdominal approach for thoracolumbar curvature. METHODS: A multicenter spinal deformity database was queried for patients who underwent an anterior approach for either Lenke I or Lenke V idiopathic scoliosis. There were 68 patients in the thoracotomy group, 44 in the thoracoscopic group, and 19 in the thoracoabdominal group. Absolute and percent-predicted values of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and total lung capacity (TLC) were evaluated preoperatively and at 2-year follow-up, and comparisons were made within and between each group. RESULTS: Comparing between groups at 2 years postoperatively, the thoracotomy group demonstrated significantly greater decreases (-10.97% and -12.97%) in both percent-predicted FEV1 and FVC, respectively, when compared with the thoracoscopic group (-4.40% and -4.73%), respectively. Percent-predicted TLC in the thoracoscopic group increased (3.19%), but decreased in the thoracotomy group (-8.00%). Subanalysis of the thoracoscopic group at 2 years revealed that the addition of a thoracoplasty (3 to 5 ribs) significantly reduced percent-predicted FEV1 (-11.6%, P = 0.0013) and percent-predicted FVC (-16.0%, P = 0.017) from baseline. Patients who underwent thoracoscopy alone without a thoracoplasty experienced no significant detrimental changes in these parameters at 2 years, and instead experienced significant increases in absolute TLC (P < 0.001) and percent-predicted TLC (P = 0.035). There were no significant changes demonstrated in the thoracoabdominal group for all 3 parameters. CONCLUSIONS: Slight declines in pulmonary function at 2-year follow-up were noted in both the thoracotomy and thoracoscopic groups, but to a significantly greater extent in those with an open thoracotomy. Significantly greater impairment in pulmonary function was seen in thoracoscopic patients who underwent thoracoplasty, whereas those without thoracoplasty either had no significant declines at 2 years or experienced slight but significant improvement. No significant diminishment was noted for the thoracoabdominal approach, despite disruption of the diaphragm.

The prevalence of indications and contraindications to cervical total disc replacement.

BACKGROUND CONTEXT: Although the prevalence of indications and contraindications to lumbar total disc replacement (TDR) has been evaluated, no study to date has quantified the potential candidacy for cervical disc replacement in practice. PURPOSE: To report the potential candidacy rate for cervical TDR from both an academic and private practice spine surgery setting. STUDY DESIGN/SETTING: Retrospective case series. PATIENT SAMPLE: Patient record review of 167 consecutive patients who underwent cervical spine surgery by 1 of 2 orthopedic spine surgeons between January 1, 2003 and January 1, 2005. OUTCOME MEASURES: Evaluation of potential candidacy for cervical TDR, with emphasis on both contraindications and indications. METHODS: In this study, we used the published contraindications and indications listed in trials of four different cervical disc arthroplasty devices: ProDisc-C (Synthes Spine, West Chester, PA), PRESTIGE LP (Medtronik Sofamor Danek, Memphis, TN), Bryan Cervical Disc prosthesis (Medtronik Sofamor Danek, Memphis, TN), and Porous Coated Motion (PCM; Cervitech, Rockaway, NJ). The proportion of patients who met both inclusion and exclusion criteria was calculated. We also examined the proportion of patients who would be candidates for cervical TDR if the indications were expanded to include the treatment for adjacent segment disease (ASD). RESULTS: Of the 167 patients (mean age 50.8 years, range 20-89 years) reviewed, 91.6% (153/167) had fusion surgery and 8.4% (14/167) had nonfusion surgery. Fifty-seven percent (95/167) had absolute contraindications to cervical TDR, and within this group the average number of contraindications was 2.1 (SD=1.2, range 0-5). Forty-three percent (72/167) met the strict inclusion criteria, and had no exclusion criteria. If the indications were expanded to include treatment for ASD, an additional 4.2% (7/167) of the patients would have qualified as candidates for cervical TDR. CONCLUSIONS: Compared with lumbar TDR, total disc replacement may have a larger potential role in the treatment of cervical degenerative conditions, as 43% of patients would have met the strict criteria for TDR candidacy, or 47% if the indications were expanded to include treatment for ASD.

Streamlining the evaluation of low back pain in children.

UNLABELLED: The workup of low back pain in children often results in overimaging so as not to miss organic back pain. The primary goal of this study was to identify which combination of imaging modalities provides the most sensitive and specific screening protocol for children with low back pain. Medical records from 100 consecutive patients between 2 and 18 years of age presenting with low back pain, without night pain or constitutional symptoms, were evaluated. A hyperextension test combined with a radiograph showed a negative predictive value of 0.81 and sensitivity of 0.90. The addition of a bone scan was highly effective in achieving good negative predictive value and sensitivity. Bone scans had perfect negative predictive value and sensitivity when symptom duration was less than 6 weeks. We identified a set of factors that is highly predictive for distinguishing organic back pain from mechanical back pain. Painless hyperextension combined with negative anteroposterior, lateral, and oblique lumbar radiographs and magnetic resonance images predicts mechanical back pain. For patients with nonneurologic back pain of less than 6 weeks duration, bone scan is the most useful screening test because it is accurate, accessible, inexpensive, and unlikely to require sedation. LEVEL OF EVIDENCE: Level III, diagnostic study.

Advances in Magnetic Resonance Imaging for the assessment of degenerative disc disease of the lumbar spine.

The intervertebral disc is characterized by a tension-resisting annulus fibrosus, and a compression-resisting nucleus pulposus composed largely of proteoglycan. Both the annulus and the nucleus function in concert to provide the disc with mechanical stability. Early disc degeneration begins in the nucleus with proteoglycan depletion. Quantitative MRI techniques have been developed to non-invasively quantify the earliest degenerative changes that occur within the disc. Our ability to identify and quantify these early biochemical changes will provide a better understanding of the pathophysiology of disc degeneration and facilitate the study of interventions that aim to halt or reverse the degenerative process.

Sacral fractures.

Sacral fractures most commonly occur after pelvic ring injuries but occasionally in isolation. Although the true incidence of sacral fractures is unknown, an estimated 30% are identified late. Sequelae of inappropriately treated or untreated sacral fractures include persistent pain, decreased mobility, and neurologic compromise. Because these fractures often result from high-energy trauma, concomitant injuries should be suspected. A thorough physical examination, including a detailed neurologic assessment and radiographic evaluation, is necessary to determine treatment. Computed tomography of the pelvis/sacrum can provide significant information about fracture pattern. Surgical intervention, often as a combination of neural decompression and stabilization, is indicated in patients with neurologic deficits, significant soft-tissue compromise, and lumbosacral instability. Patient satisfaction with surgical intervention has not been definitively documented, although neurologic improvement with timely intervention has been noted.

Delayed Postoperative Neurologic Deficits in Spinal Deformity Surgery.

STUDY DESIGN: A cross-sectional survey of surgeon members of the Scoliosis Research Society (SRS). OBJECTIVE: This study sought to characterize the incidence, clinical presentation, diagnostic workup, treatment, and neurologic prognosis following delayed postoperative neurologic deficit (DPND) in patients undergoing spinal deformity surgery. SUMMARY OF BACKGROUND DATA: DPND is a potentially devastating condition following spinal surgery, characterized by the development of a neurological deficit within hours or days of the surgical procedure. To date, only case reports and small case series have been published on the topic. METHODS: We developed a survey to characterize DPND following spinal deformity surgery. This survey was distributed to surgeon members of the SRS through email and standard mail. The overall response rate was 38% (352/929). RESULTS: Our results suggest an estimated DPND incidence of 1 of 9910 cases (0.01%). Eighty-one surgeons (23%) experienced at least 1 DPND in the past 10 years (92 total cases). Most common diagnoses were scoliosis (69%), kyphosis (23%), and spondylolisthesis (14%); 20% were revision surgeries. The number of hours to deficit onset was as follows: 1 to 12 (36%), 13 to 24 (27%), 25 to 48 (27%), more than 48 (10%). The most commonly cited sources of injury included ischemic injury (38%) and cord compression (15%). Forty-one percent experienced complete neurologic recovery, 26% partial, and 33% no recovery. Twenty-one percent of patients achieved final neurologic status within 1 week, 38% by 1 month, and 73% by 6 months. Patients with compression-related DPND had a significantly greater likelihood of experiencing some neurologic recovery (≥1 ASIA Grade) than ischemia-related DPND (86% versus 51%, P = 0.049). CONCLUSIONS: DPND occurs at an estimated incidence of 0.01%. Sixty-three percent of DPND cases occurred within the first 24 hours and 90% within 48 hours. Complete (41%) or partial (26%) neurologic recovery may be expected, especially in compression-related DPND, emphasizing the need for perioperative vigilance, prompt recognition, and early intervention. LEVEL OF EVIDENCE: 4.

Septic arthritis of the glenohumeral joint: a review of 23 cases.

Infection of the glenohumeral joint is an uncommon yet devastating condition. The objective of this study was to review the incidence, risk factors, presentation, and treatment for this disorder. Twenty-three culture-positive cases of septic arthritis of the glenohumeral joint were identified and treated at the authors' institution between 1986 and 2000. Eighty-seven percent of patients had at least one serious systemic illness, and on average had two. Fifty-two percent had a different primary site of infection identified. Staphylococcus aureus was identified as the infectious organism in 70% of cases, 17% of which were found to be methicillin-resistant S. aureus. Patients admitted to the orthopedic service were more likely to undergo surgical treatment. Patients treated surgically had shorter hospital stays than those treated with serial aspirations alone. Shoulder infections affect patients who are older and have multiple systemic diseases. Surgical treatment of shoulder infections, when compared to aspiration alone, is associated with a shorter hospital stay. Glenohumeral infection is a debilitating affliction even when control of the infection can be achieved.

Cervical spinal cord dimensions and clinical outcomes in adults with klippel-feil syndrome: a comparison with matched controls.

Study Design Retrospective case-control study. Objectives To confirm the fact that spinal cord dimensions are smaller in adults with Klippel-Feil syndrome (KFS) than in pediatric patients with KFS and to compare the clinical characteristics and outcomes of neurologic complications in patients with KFS with matched controls. Methods We performed an independent 1:2 case-control retrospective radiographic and chart review of a consecutive series of adults with KFS who underwent surgical intervention. The control group consisted of consecutive non-KFS surgical patients. Patients were matched in 1:2 case-control manner. Their charts were reviewed and the clinical characteristics were compared. Axial T2-weighted magnetic resonance imaging (MRI) was used to measure the anteroposterior and mediolateral axial spinal cord and spinal canal at the operative levels and measurements were compared. Results A total of 22 patients with KFS and 44 controls were identified. The KFS group had a tendency of more myeloradiculopathy, and the control group had a tendency toward more radiculopathy. Both tendencies, however, were not significantly different. MRIs of 10 patients from the KFS group and 22 controls were available. There was no difference in the area of both spinal cord and canal at the operative levels. Conclusion Contrary to the finding in previous reports on pediatric patients, there were no differences between KFS and well-matched control groups in terms of age of onset, presentation, revision rate, complication rate, surgical outcome, and cross-sectional spinal cord and canal dimensions at the operative level.

Body image in patients with adolescent idiopathic scoliosis: validation of the Body Image Disturbance Questionnaire--Scoliosis Version.

BACKGROUND: Appearance concerns in individuals with adolescent idiopathic scoliosis can result in impairment in daily functioning, or body image disturbance. The Body Image Disturbance Questionnaire (BIDQ) is a self-reported, seven-question instrument that measures body image disturbance in general populations; no studies have specifically examined body image disturbance in those with adolescent idiopathic scoliosis. This study aimed to validate a modified version of the BIDQ in a population with adolescent idiopathic scoliosis and to establish discriminant validity by comparing responses of operatively and nonoperatively treated patients with those of normal controls. METHODS: In the first phase, a multicenter study of forty-nine patients (mean age, fourteen years; thirty-seven female) with adolescent idiopathic scoliosis was performed to validate the BIDQ-Scoliosis version (BIDQ-S). Participants completed the BIDQ-S, Scoliosis Research Society (SRS)-22, Children's Depression Index (CDI), and Body Esteem Scale for Adolescents and Adults (BESAA) questionnaires. Descriptive statistics and Pearson correlation coefficients were calculated. In the second phase, ninety-eight patients with adolescent idiopathic scoliosis (mean age, 15.7 years; seventy-five female) matched by age and sex with ninety-eight healthy adolescents were enrolled into a single-center study to evaluate the discriminant validity of the BIDQ-S. Subjects completed the BIDQ-S and a demographic form before treatment. Independent-sample t tests and Pearson correlation coefficients were calculated. RESULTS: The BIDQ-S was internally consistent (Cronbach alpha = 0.82), and corrected item total correlations ranged from 0.47 to 0.67. The BIDQ-S was significantly correlated with each domain of the SRS-22 and the total score (r = -0.50 to -0.72, p ≤ 0.001), with the CDI (r = 0.31, p = 0.03), and with the BESAA (r = 0.60, p < 0.001). BIDQ-S scores differed significantly between patients (1.50) and controls (1.06, p < 0.005), establishing discriminant validity. CONCLUSIONS: The BIDQ-S is an internally consistent outcomes instrument that correlated with the SRS-22, CDI, and BESAA outcomes instruments in a scoliosis population. The scores of the patients with scoliosis indicated greater back-related body image disturbance compared with healthy controls. To our knowledge, this user-friendly instrument is the first to examine body image disturbance in adolescent idiopathic scoliosis, and it provides a comprehensive evaluation of how scoliosis-related appearance concerns impact psychosocial and daily functioning.

Can low-grade spondylolisthesis be effectively treated by either coflex interlaminar stabilization or laminectomy and posterior spinal fusion? Two-year clinical and radiographic results from the randomized, prospective, multicenter US investigational device exemption trial: clinical article.

OBJECT: Posterolateral spinal fusion (PSF) has long been the standard of care for degenerative spondylolisthesis, but less invasive, motion-preserving alternatives have been proposed to reduce the complications associated with fusion while still providing neural decompression and stabilization. The object of the current study is to evaluate the safety and efficacy of coflex Interlaminar Stabilization compared with PSF to treat low-grade spondylolisthesis with spinal stenosis. METHODS: This is a prospective, randomized, multicenter FDA investigational device exemption (IDE) trial comparing coflex Interlaminar Stabilization with laminectomy and PSF. A total of 322 patients from 21 sites in the US were enrolled between 2006 and 2008 for the IDE trial. The current study evaluated only the subset of patients from this overall cohort with Grade 1 spondylolisthesis (99 in the coflex group and 51 in the fusion group). Subjects were randomized 2:1 to receive decompression and coflex interlaminar stabilization or decompression and posterolateral spinal fusion with spinal instrumentation. Data collected included perioperative outcomes, Oswestry Disability Index (ODI), back and worse leg visual analog scale (VAS) scores, 12-Item Short Form Health Survey, Zurich Claudication Questionnaire (ZCQ), and radiographic outcomes at a minimum of 2 years. The FDA criteria for overall device success required the following to be met: 15-point reduction in ODI, no reoperations, no major device-related complications, and no postoperative epidural injections. RESULTS: At a minimum of 2 years, patient follow-up was 94.9% and 94.1% in the coflex and fusion control groups, respectively. There were no group differences at baseline for any demographic, clinical, or radiographic parameter. The average age was 63 years in the coflex cohort and 65 years in the fusion cohort. Coflex subjects experienced significantly shorter operative times (p < 0.0001), less estimated blood loss (p < 0.0001), and shorter length of stay (p < 0.0001) than fusion controls. Both groups experienced significant improvements from baseline at 2 years in ODI, VAS back, VAS leg, and ZCQ, with no significant group differences, with the exception of significantly greater ZCQ satisfaction with coflex at 2 years. FDA overall success was achieved in 62.8% of coflex subjects (59 of 94) and 62.5% of fusion controls (30 of 48) (p = 1.000). The reoperation rate was higher in the coflex cohort (14 [14.1%] of 99) compared with fusion (3 [5.9%] of 51, p = 0.18), although this difference was not statistically significant. Fusion was associated with significantly greater angulation and translation at the superior and inferior adjacent levels compared with baseline, while coflex showed no significant radiographic changes at the operative or index levels. CONCLUSIONS: Low-grade spondylolisthesis was effectively stabilized by coflex and led to similar clinical outcomes, with improved perioperative outcomes, compared with PSF at 2 years. Reoperation rates, however, were higher in the coflex cohort. Patients in the fusion cohort experienced significantly increased superior and inferior level angulation and translation, while those in the coflex cohort experienced no significant adjacent or index level radiographic changes from baseline. Coflex Interlaminar Stabilization is a less invasive, safe, and equally efficacious clinical solution to PSF to treat low-grade spondylolisthesis, and it appears to reduce stresses at the adjacent levels. Clinical trial registration no.: NCT00534235 (ClinicalTrials.gov).

Is radiation-free diagnostic monitoring of adolescent idiopathic scoliosis feasible using upright positional magnetic resonance imaging?

STUDY DESIGN: Prospective clinical trial. OBJECTIVE: The purpose of this study was to determine if an upright positional magnetic resonance imaging (MRI) protocol could produce reliable spinal curvature images and measurements compared with traditional radiograph. SUMMARY OF BACKGROUND DATA: Concerns about the oncological potential from cumulative doses of ionizing radiation in children and adolescents being monitored for adolescent idiopathic scoliosis (AIS) initiated a search for radiation-free diagnostic imaging modalities, including MRI. We submit that upright, positional MRI (uMRI) produces reliable spinal curvature images compared with traditional radiograph. METHODS: Twenty-five consecutive patients (16 female; 9 male; average age, 14.6 yr; range, 12-18 yr) with a diagnosis of AIS were enrolled. Average major curve magnitude was 30° (range, 6°-70°). Subjects received anterior-posterior and lateral plain radiographical scoliosis imaging followed within 1 week by uMRI. MRI data acquisition was performed in less than 7 minutes. Two independent observers performed all Cobb angle, T5-T12 kyphosis, and vertebral rotation measurements for comparison. The Pearson correlation method was performed to compare radiograph to uMRI measurements, while inter-rater and intrarater correlations were performed to assess reliability. RESULTS: We found outstanding correlation between all plain film radiography and uMRI measurements (P = 0.01); major Cobb angles (R = 0.901), minor Cobb angles (R = 0.838), and kyphosis (R = 0.943). Inter-rater reliability for both radiographical and MRI measurements of major Cobb angles (R = 0.959, 0.896, respectively), minor Cobb angles (R = 0.951, 0.857, respectively), and vertebral rotation (R = 0.945) were outstanding. Intrarater reliability for both radiographical and MRI measurements of major Cobb angles (R = 0.966, 0.966, respectively) and minor Cobb angles (R = 0.945, 0.943, respectively) were also outstanding. CONCLUSION: Our results show that uMRI is capable of producing coronal and sagittal plane measurements that highly correlate with traditional plain film radiographical measurements. This, in addition to reliable vertebral rotation measurements, makes uMRI a valuable, radiation-free alternative/substitute for diagnostic evaluation in AIS.

Low-density versus high-density thoracic pedicle screw constructs in adolescent idiopathic scoliosis: do more screws lead to a better outcome?

BACKGROUND CONTEXT: Thoracic pedicle screw (TPS) constructs have improved curve correction measurements compared with hook and hybrid constructs in the treatment of adolescent idiopathic scoliosis (AIS), but the optimal implant density, or the number of screws per level, remains unknown in the treatment of flexible thoracic curves. PURPOSE: To determine how implant density affects clinical outcome, radiographic outcome, and cost in the treatment of Lenke Curve Type I AIS. STUDY DESIGN: A retrospective clinical study. PATIENT SAMPLE: Ninety-one consecutive AIS patients with Lenke Type I curves who underwent surgical correction with a minimum follow-up of 24 months. OUTCOME MEASURES: Radiographic outcomes included assessment of preoperative and 2-year postoperative thoracic Cobb angle, T5-T12 kyphosis, and curve flexibility. We also assessed SRS-22 outcome measures and thoracic angle of trunk rotation (ATR) before surgery and at the 2-year postoperative time point. The cost of each construct was also evaluated. METHODS: Bivariate analysis was conducted between implant density and the following factors: percent correction of the major curve, ATR, and change in kyphosis. The correlation between curve flexibility and percent correction of the major curve was determined. Patients were then divided into two groups: the low-density (LD) TPS group defined by implant density below the mean number of screws per level for the entire cohort (less than 1.3 screws per level) and the high-density (HD) TPS group defined by implant density above the mean number of screws per level (more than 1.3 screws per level). Independent sample t tests were used to compare demographic data as well as radiographic and clinical outcomes at baseline and at follow-up between the two groups. RESULTS: Sixty-one female and 30 male patients met inclusion criteria. No significant correlations were found between implant density and the following parameters: percent correction of the major curve (p=.25), ATR (p=.75), and change in T5-T12 kyphosis (p=.40). No correlation was found between curve flexibility and percent correction of the major curve (p=.54). The LD group consisted of 57 patients, whereas the HD group had 34 patients. There were no differences between the HD group and the LD group in regard to major curve correction, change in T5-T12 kyphosis, or change in ATR. Total implant costs were significantly higher in the HD group ($13,272 vs. $10,819; p<.01). The SRS-22 image domain and overall score improved at 2 years within both groups, but there were no group differences in any of the SRS-22 domains or the overall score. CONCLUSIONS: We identified no clinical, radiographic, perioperative, or complication-related advantage of constructs with higher TPS implant density in this patient cohort with flexible idiopathic scoliosis. Cost was significantly higher with HD constructs in comparison with LD constructs. Optimal implant density chosen by the surgeon should rely on a number of factors including curve magnitude and rigidity, bone density, and desired correction.

Decompression and Coflex interlaminar stabilization compared with decompression and instrumented spinal fusion for spinal stenosis and low-grade degenerative spondylolisthesis: two-year results from the prospective, randomized, multicenter, Food and Drug Administration Investigational Device Exemption trial.

STUDY DESIGN: Prospective, randomized, multicenter, Food and Drug Administration Investigational Device Exemption trial. OBJECTIVE: To evaluate the safety and efficacy of Coflex interlaminar stabilization compared with posterior spinal fusion in the treatment of 1- and 2-level spinal stenosis and degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Long-term untoward sequelae of lumbar fusion for stenosis and degenerative spondylolisthesis have led to the search for motion-preserving, less-invasive alternatives. METHODS: Three hundred twenty-two patients (215 Coflex and 107 fusions) from 21 sites in the United States were enrolled between 2006 and 2010. Subjects were randomized to receive laminectomy and Coflex interlaminar stabilization or laminectomy and posterolateral spinal fusion with spinal instrumentation in a 2:1 ratio. Overall device success required a 15-point reduction in Oswestry Disability Index, no reoperations, no major device-related complications, and no postoperative epidural injections. RESULTS: Patient follow-up at minimum 2 years was 95.3% and 97.2% in the Coflex and fusion control groups, respectively. Patients taking Coflex experienced significantly shorter operative times (P < 0.0001), blood loss (P < 0.0001), and length of stay (P < 0.0001). There was a trend toward greater improvement in mean Oswestry Disability Index scores in the Coflex cohort (P = 0.075). Both groups demonstrated significant improvement from baseline in all visual analogue scale back and leg parameters. Patients taking Coflex experienced greater improvement in Short-Form 12 physical health outcomes (P = 0.050) and equivalent mental health outcomes. Coflex subjects experienced significant improvement in all Zurich Claudication Questionnaire outcomes measures compared with fusion (symptom severity [P = 0.023]; physical function [P = 0.008]; satisfaction [P = 0.006]). Based on the Food and Drug Administration composite for overall success, 66.2% of Coflex and 57.7% of fusions succeeded (P = 0.999), thus demonstrating noninferiority. The overall adverse event rate was similar between the groups, but Coflex had a higher reoperation rate (10.7% vs. 7.5%, P = 0.426). At 2 years, fusions exhibited increased angulation (P = 0.002) and a trend toward increased translation (P = 0.083) at the superior adjacent level, whereas Coflex maintained normal operative and adjacent level motion. CONCLUSION: Coflex interlaminar stabilization is a safe and efficacious alternative, with certain advantages compared with lumbar spinal fusion in the treatment of spinal stenosis and low-grade spondylolisthesis. LEVEL OF EVIDENCE: 1.

Mitigating adverse event reporting bias in spine surgery.

BACKGROUND: Recent articles in the lay press and literature have raised concerns about the ability to report honest adverse event data from industry-sponsored spine surgery studies. To address this, clinical trials may utilize an independent Clinical Events Committee (CEC) to review adverse events and readjudicate the severity and relatedness accordingly. We are aware of no prior study that has quantified either the degree to which investigator bias is present in adverse event reporting or the effect that an independent CEC has on mitigating this potential bias. METHODS: The coflex Investigational Device Exemption study is a prospective randomized controlled trial comparing coflex (Paradigm Spine) stabilization with lumbar spinal fusion to treat spinal stenosis and spondylolisthesis. Investigators classified the severity of adverse events (mild, moderate, or severe) and their relationship to the surgery and device (unrelated, unlikely, possibly, probably, or definitely). An independent CEC, composed of three spine surgeons without affiliation to the study sponsor, reviewed and reclassified all adverse event reports submitted by the investigators. RESULTS: The CEC reclassified the level of severity, relation to the surgery, and/or relation to the device in 394 (37.3%) of 1055 reported adverse events. The proportion of adverse events that underwent reclassification was similar in the coflex and fusion groups (37.9% compared with 36.0%, p = 0.56). The CEC was 5.3 (95% confidence interval [CI], 2.6 to 10.7) times more likely to upgrade than downgrade the adverse event. The CEC was 7.3 (95% CI, 5.1 to 10.6) times more likely to upgrade than downgrade the relationship to the surgery and 11.6 (95% CI, 7.5 to 18.8) times more likely to upgrade than downgrade the relationship to the device. The status of the investigator's financial interest in the company had little effect on the reclassification of adverse events. CONCLUSIONS: Thirty-seven percent of adverse events were reclassified by the CEC; the large majority of the reclassifications were an upgrade in the level of severity or a designation of greater relatedness to the surgery or device. CLINICAL RELEVANCE: An independent CEC can identify and mitigate potential inherent investigator bias and facilitate an accurate assessment of the safety profile of an investigational device, and a CEC should be considered a requisite component of future clinical trials.

Quantification of intradiscal pressures below thoracolumbar spinal fusion constructs: is there evidence to support "saving a level"?

STUDY DESIGN: In vitro cadaveric study. OBJECTIVE: The purpose of this study was to quantify the relative biomechanical protection resulting from "saving a level" in long spinal fusions. SUMMARY OF BACKGROUND DATA: "Saving levels" in spinal deformity surgery is desirable. Constructs with lowest instrumented vertebra (LIV) in the lumbar spine may increase loads on unfused lumbar intervertebral discs, leading to accelerated disc degeneration. No study to date has quantified the relative pressure changes that occur in the unfused caudal discs with progressively longer fusions. METHODS: We used a validated in vitro cadaveric long fusion model to assess intradiscal pressures (IDPs) below simulated fusions. Eight fresh frozen T8-S1 specimens were instrumented from T8 to L5. A follower-type loading system and 7.5-N·m moments were applied in flexion and extension. IDP profiles were assessed with a pressure transducer. After acquiring IDP measurements at a given construct length, the rod was cut 1 level higher until LIV = T12. IDP data from each unfused disc were averaged and normalized to the mean value of the disc when immediately subjacent to the LIV. RESULTS: In both flexion and extension, the mean normalized IDP of the unfused discs below the LIV increased with increasing fusion length. For each 1-level increase in construct length, pressure increased by 3.2% ± 4.8% in flexion and 4.3% ± 4.5% in extension for each unfused disc. Although the differences in pressure for a given unfused disc with differing LIV were not significant, there were significant differences between unfused discs at a given LIV. With shorter fusion lengths, pressure in the disc immediately subjacent to the fusion was consistently greater than for the caudal-most discs. CONCLUSION: Unfused caudal lumbar discs experienced increased IDPs with increasing length of instrumentation, most notably at the subjacent discs closest to the LIV.